Hello,
I have Windows Vista with Office 2007. Microsoft Outlook has been working fine for 18 months but has suddenly developed a fault when sending emails with attachments containing photos or documents with pictures on them. Email goes to Outbox aand is sent but remains in Outbox and is not recorded in Sent Mail. Outbox sends email again and again and again .......... Recipient just keeps on getting copies.
Appreciate advice.

this problem occurs when the "sent items" file/folder is full. God knows how and why it ditermines it's full even though you have a lot of space on the HD)

you can do one of the following:

delete messges from the sent items folder. it's better to delete all the messages if you don't need them.

or:

you can delete the file that contains the sent items (the file with the dbx format)
if you delete it microsoft outlook will make a new blank copy .
if you want to know where the file is located hold your mouse on the sent items , right click and then properties, you will see the location.

that will do it but if that don't work try deleting messages from the inbox too.

I have the same problem as above, also the same software versions, I have done what u suggested deleted some 2000 emails x my sent and and inbox folders along with about 6000 from deleted folder but still the same problem exists. I have been using this combination for a year or two and now suddenly this problem, it drives you nuts, I drag the email from the outbox to drafts to stop it sending more copies, one friend said i sent the same email with photos over 100 times, any further suggestings, please, before I go nuts.